Inatallation:

1) Unpack content of the tarball in desired place
2) Edit the invocation of 'newpop' in the 'build_pop' script to choose
   appriate version of X support.  As is the build_pop script links
   with Motif (or Lesstif).  The alternative (commented out) line
   links with Xt.
3) run the 'build_pop' script to recompile (on fast machine it
   should take less than 30 seconds)
4) move 'poplog' script to some directory in the path and adjust
   the 'poplogroot' variable to point to root of the installed
   tree (that is directory containing this file).